a. Field of the Invention
Broadly speaking, this invention relates to a control circuit for helicopter rotor tip lights, and the like. More particularly, in a preferred embodiment, this invention relates to a control circuit for controlling the operation and/or intensity of helicopter rotor tip lights without the necessity of providing a physical connection between the main body of the helicopter and the rotating rotor blades.
B. Discussion of the Prior Art
Helicopter pilots have found that in night time operations it is highly advantageous to illuminate the tips of their rotor blades. For example, such illumination assists pilots to safely position their helicopters when flying in close formation, assists in landing the helicopters, and provides an indication of range by virtue of the angular subtent of the described light path.
Of course, some means must be provided to supply power to the rotor tip lights and it must also be possible to energize and deenergize the lights at will because it would obviously be inadvisable to have the rotor tip lights illuminated when flying over hostile territory, for example. Further, it is also advantageous to be able to alter on command the intensity of the illumination, for example, from high to medium to low, depending on the circumstances and use to which the illumination is to be put.
The control panel for these functions must, of course, be physically located close to the pilot and heretofore the connection between the panel circuitry in the main body of the helicopter and the rotor tip lights has been accomplished by means of slip-rings and commutators positioned about the rotor shaft with wires running internally through the rotor blades.
Unfortunately, this has not proved to be satisfactory in practice due to the high speed at which the shaft rotates as well as the high g-forces and vibration to which the commutators, wiring and slip-rings are subjected during flight. The problem, then, is to devise some technique for both energizing and controlling the rotor tip lights which does not rely on a direct mechanical and electrical connection between the rotating blades and the main body of the helicopter.